轴向约束钢框架柱火灾升温下屈曲后性能研究  

Post-Buckling Behavior of Axially Restrained Steel Columns in Fire

作　　者：王培军[1] 李国强[1] 

机构地区：[1]同济大学土木工程学院,上海200092

出　　处：《同济大学学报（自然科学版）》2008年第4期438-443,共6页Journal of Tongji University:Natural Science

基　　金：国家杰出青年科技基金资助项目(50225825)

摘　　要：提出了一种改进的Jezék方法,用于火灾升温下轴向约束钢框架柱屈曲后性能分析,高温条件下钢材的应力-应变关系考虑了钢柱屈曲后凸侧可能出现的卸载现象.对轴向约束钢柱的参数分析表明,随着约束刚度的增大,钢柱附加轴力增大,屈曲温度降低,但轴向约束对屈曲后性能影响很小;荷载比大的构件抗火性能差,屈曲温度低,屈曲后轴力下降迅速;长细比小的构件,屈曲后轴力下降缓慢,屈曲后抗火性能显著提高;初弯曲大的构件,屈曲温度低,附加轴力小.在局部火灾下,利用约束钢柱的屈曲后性能,可显著提高其抗火性能.A modified Jezék method is presented to study the post-buckling behavior of axially restrained steel columns at elevated temperatures in fire. The possible unloading behavior of steel at changing temperature is considered in the stress-strain relationship when buckling presents. Parametric studies show that： the existence of the axial restraint causes an increase in the axial force before the column buckles and will reduce the buckling temperature of the column, however it has little influence on the column＇s post-buckling behavior; columns with great load ratio have little fire resistance; the critical temperature of a column with small slenderness ratio can be greatly improved by utilizing the post-buckling behavior; the additional compression force of a column with greater initial out of plane straightness will be smaller. In a localized fire, the fire resistance of axially restrained steel columns can be increased by utilizing the Wast-buckling behavior.

关 键 词：钢框架柱 火灾 临界温度 屈曲后性能 轴向约束 

分 类 号：TU393.2[建筑科学—结构工程]